Transmitter for fire alarm systems



Sept. 6, 1932.

G. F. HflRTER TRANSIITTER FOR FIRE ALARI SYSTEIS Filed Ot'sl'. 19, 1927 5 Shoots-Shea 1 Sept. 6, 1932. v s. F. HARTER I 1,375,810.

' TRANSMITTER FOR .FIRE AL'm sYs'raIs Filed Oct. 19. 1927 -5 Sheets-Sheet 2 G. F. HARTER TRANSIITTER FOR FIRE ALARI SYSTEIS Sept. 6, 1932. 1

Filed Oct. 19. 1927 5' sheets-sheep s anbmtoz Sept. 5,1932.

G. F. HARTER TRANSIITTER FOR FIRE ALARM 'SYSTEIS Filed Oct. 19. 1927 5 Sheets-Sheet 4 auoentoz p 1932. a. F. HARTER 1,875,810

TRANSIITTER FOR FiRE ALARI SYSTBIS Filed 001%. 19. 192? 5 Sheets-Sheet 5 avwmtoz Patented Sept. 6, 1932 un -Tao STATES PATENT OFFICE enoaen r. ma or srnmermnnjmssaonusnrrs, assronon TO THE sramu'nn ELECTRIC rum company, or SPRINGFIELD, uassacnusm'rs, A oonromrrou or ooitnnorrour 'rnansmrrna FOR mm ALARM SYSTEMS Application fled October 19, 192 7.' Serial No. 227,095.

This invention relates to relay or transmitter mechanisms for opening and closing or otherwise varying one or morecircuits under the control of what may be termed a master circuit (or two or more such circuits) and its chief object is to provide for the purpose a mechanism of simple construction capable of operating with unfailing reliability for lon periods of time. Another object is to provide such a relay or transmitter mechanism for use in fire alarm systems .to open and close or otherwise vary one or more signal circuits according to a prearranged code. A further object is to provide a relay or transmittermechanism which will also control one or more supervisory circuits, to give warning of failure to restore the relay or transmitter itself to operative condition after it has transmitted the prescribed signals. To these and other ends the invention comprises the novel features and combinations hereinafter described.

Of the various forms in' which the inven- .tion can be embodied I have selected two which at the present time are believed to exhibit the invention in its most convenient and effective forms. It is to be understood,'however, that the transmitters herein specifically described can be employed toadvantage with.

such modification, if any, as may be necessary or desirable, in other systems also.

Referring now to the accompanying draw 1ngs 1 and 2 are wiring diagrams illustrating two fire alarm systems. In Fig. 1 the main or master circuit is normally closed through a suitable current-reducing resistance which is shunted out of the circuit by the act of turning in an alarm of fire. This has an effect practically equivalent to closing a normally open circuit. In Fig. 2 the normally closed main or master circuit lacks the current-reducing resistance and the act of turning in an alarm opens the circuit.

Fig. 3 is a side view of a relay or transmitter mechanism embodying my invention, for transmitting fire alarm slgnals according to a predetermined code and for controlling one or more supervisory circuits of a fire alarm system. The figure shows the 'contactsby which the alarm and supervisory circuits are controlled, and shows the positions of the contacts after the alarm signals have been transmitted and before the system has been restored to normal condition.

Fig. 4 is an elevational view of the relay or transmitter illustrated in Fig. 3 but showing the other side of the device.

Fig. 5 is an end view from the left of Fig. 3 and right of Fig. 4. .0

Fig. 6 is a longitudinal section taken on a. vertical plane just inside of the side plate shown in Fig. 3, showing the spring-driven mechanism with its various parts in their normal positions.

Fig. 6a is a detail perspective view showing the normal position of the locking devices shown in side view in Fig. 6.

Fig. 7 is a detail section, o n the same plane as Fig. 6, showing the; position of the locking devices just after the spring-driven mechanism has been unlocked byrthe turning inofanalarm.

Fig. 8 is a detail side yiemillustrating the restoration of the locking detent-to normal -75 condition after an alarm has been; turned in, such restoration being efi'ected byor dependent upon complete re-winding of the spring which drives the mechanism.

Fig. 9 is a detail longitudinal section, taken on a vertical plane just inside of the side plate shown in Fig. 4, to show the positions of the spring barrel and the associated winding lever after the mechanism has ceased to transmit the code signals.

Fig. 10 is a longitudinal section similar to Fig. 6 but illustrating different locking devices. Fig. 10a is a detail perspective view. illustrating the locking devices-of Fig. 10, in normal position. 1

Fig. 106 is a detail side. view. showings. modified means for controlling the locking devices. y

Fig. 11 is a detail longitudinal-sectionon the same plane as Fig. 10, showing the posi: tion of certain parts just afterthe spri driven mechanism'has been unlocked by t e turning inof an alarm. y I I Referring nowto Fig. 1, S, S-,jSrepresenjt master code-transmitter 18 stations at which an alarm may be turned in. These may be of the Break Glass type, preferably the ty e in which the mere act of breaking the g ass front of the box causes the alarm to be sent. As, shown, each station has a pair of contacts across the resistance R, the several pairs of contacts being in multiple, so that when the glass at any station is broken the bridge piece I) closes upon the contacts and thus shunts out the resistance. Normally current is flowing in the station-box or master circuit from the ne ative terminal of the high voltage battery through terminal 10, wires 11 and 12, milliammeter M, wires 13, 15, normally closed contacts 16, 17, wire 19, relay 20 (termed the station relay wire 21, terminal 22, wire 23, station break-glass boxes S, resistance R, station boxes S, wire 24, terminal 25, wire 26 and terminal 27 back to the battery. By reason of the resistance R in the circuit the normal current is too weak to actuate the armature of the master code transmitter 18 but is strong enough to energize the station rela 20 and thus holdits armature down, keeping contacts 28 29 unbridged.

The circuit just trace is supervised. That is, if anything happens WhlCh would disable the circuit, as for example a broken wire, a loose connection, or failure of the battery 11, an audible or visible signal is ven to apprise the attendant of the defect. us, suppose that the circuit is broken or that for any other reason the current through the station relay 2O falls to a value such that the latter no longer holds its contacts open. Current now flows from low voltage battery L through terminal 33, wire 34,"trouble bell 35, wires 36, 37, contact 29, bridge 38, contact 28, wire 39, 40, and terminal 41 back to the battery. With the circuit in normal condition, suppose that an alarm is turned in, by breakin the glass at one of the alarm stations. This shunts out resistance R, thereby strengthening the current through the master code transmitter 18 enough to actuate its armature, which releases stop 30 and permits the spring driven mechanism of the transmitter to start and rotate the cams 41a, 42a. The former permits spring contacts 16, 17 to open. Remembering that these contacts are in series with the winding of station relay 20, it will be seen the separation of the contacts deener- 'zes the relay, allowing its armature to ridge contacts 28, 29 and thus close the circuit last traced through the trouble bell 35. At the same time, cam 42a swings contact 43 over against contact 44, and current then flows from main battery H through terminal 10, wires 11, 12, 47, milliammeter M, wire 13, relay 48 (termed the contactor), wire 49, contacts 43, 44 wires 50, 51, terminal 25, wire 26 and terminal 27 back to the battery. Contactor 48, thus energized, draws down its two contacts 52, 62 (normally held up by the springs) and current then flows rom main attery H, through terminal 10, wires 11, 12, bridge contact 53, wire 54, resistance 55, wire 56, terminal 57, wire 58, bells B, B, B, wire 59, terminal 60, wire 61, bridge 62, wire 51, terminal 25, wire 26 and terminal 27 back to the battery. Also current flows at the same time in the parallel circuit of bells B, B, B, containin resistance 63, as follows: main battery terminal 10, wires 11, 12, bridge contact 53, wire 67, resistance 63, wire 67a, terminal 68, wire 69, bells B, B, B, wire 70, terminal 71, wires 72, 50, 51, terminal 25, wire 26, and terminal 27 back to the batter As cam 42a revolves, the circuit traced a ove through contactor 48 is broken, the bridge pieces 53, 62 rise and break the bell circuits, then the next tooth on the cam closes the contactor circuit again, etc., the operation being repeated as long as the mechanism of the master code transmitter 18 continues to run. When the mechanism stops, the contactor circuit just referred to is left open at contacts 43, 44. Contacts 16, 17 are also left open, and hence the trouble bell 35 continues to ring until the entire system is restored to normal condition by replacing the glass at the station where the alarm was turned in and by resetting the master code transmitter.

The system also has a balanced relay 42 provided with separate windings connected with the two batteries and so designed with respect thereto that under normal conditions of current and voltage the separate magnetizations balance or neutralize each other and hence the pivoted armature (not shown) is not actauted to close either pair of associated contacts. If, however, the current through either winding falls below a predetermined minimum the relay will be unbal: anced and the armature will close the appropriate contacts. It will be seen that under normal conditions weak current (due to the number of bells, relays, and resistances then in series) flows from main battery H through terminal 10, wire 12, 47, milliammeter M, wire13, contactor 48 (the current being too weak to energize the latter), wire 49, normally closed contacts 43, 64 of the master code transmitter 18, wire 65, high voltage winding of the balance relay 42, wires 66, 61, terminal 60, wire 59, bells B, B, B, wire 58, terminal 57, wire 56, resistance 55, wires 54, 67 resistance 63, wire 67a, terminal 68, wire 69, bells B, B, B (which are thus in series with bells B, B, B), wire 7 0, terminal 71, wires 72, 50, 51, terminal 25, wire 26, and terminal 27 back to the battery. At the same time current flows from the low voltage battery L through terminal 33, wires 34, 73, low voltage winding of balanced relay 42, wires 74, 40, and terminal 41 back to the battery. If, now, a break occurs in the series bell circuit traced above, the high voltagp winding will be deprived of current and t e relay will therefore be unbalanced, permitting t e magnetization due to the low voltage winding to close the associated contacts 75. Current then flows from batter L through terminal 33, wire 34, trouble be 1 35, wire 36, contacts 7 5, wire 40 and terminal 41 back to the battery, thus giving warning that the station circuit is out of order. Obviously the same result will occur if the main or high-voltage battery should fail. Now suppose that the low voltage battery should fail, or its circuit through the low volta e winding of the balanced relay should broken. In that case the relay would be unbalanced and the contacts 76 would be closed by the magnetization produced by the high voltage winding, current then flowing from battery H through terminal 10, wires 11, 12, contacts 76, wire 77, trouble bell 78, wire 79 and terminal 27 back to the battery. And of course the bell will continue to ring until the trouble is located and remedied.-

From the foregoing it will be seen that all the circuits of the system are supervised, warning being given if either battery fails or if a break occurs in an circuit.

The system shown in ig. 2 differs from that shown in Fig. 1 in that the alarm boxes are in series, and are of the type in which breaking the glass opens the box circuit. In this system it will be evident that the box circuit has normally the full voltage of the main battery, and that an accidental break in the box circuit will have the same result as breaking the glass at one of the station boxes and hence will cause a general alarm and not merely a trouble alarm as in the system of Fig. 1.

eferring now to Figs. 3, 4 and 5, the transmitter mechanism is mounted between and on a pair of spaced side plates 100, 101, having feet 102 by which the device may be mounted in horizontal or vertical position. At the rear end is a shelf 103 supporting the transmitter magnets 104 and the insulated terminals 105 for connecting the magnets in the proper circuit. On side plate 100 are two insulating blocks, one supporting spring contacts 16a, 17a, and the other supporting spring contacts 43a, 44a, 64a. The former are normally held closed by cam 41a (not so shown in Fig. 3) and contacts 43a and 64a are normally held closed by their own resiliency. The mechanism which actuates cams 41a and 420 (the latter actuating contact 43a) is itself actuated by a spring (not shown) housed in a barrel or drum 106 having a driving gear 107. The spring is wound by a manual lever 108, loose on the drum shaft but adapted to engage a stud 109 on the adjacent gear 107, so that to wind the spring it is only necessary to depress the lever. A stop 110 on the side plate 101 limits the winding movement of the lever, and the other end of the same stop, in the ath of a stud 111,1imits the unwinding o the spring in case it should be accidentally released. Initial tension may be put on the spring by means ofthe winding stud or journal 112, under the control of the conventional ratchet 113 and spring-actuated pawl 114.

Cam 41a is rotated b shaft 115, on which it is rotatably adjusta 1e, and shaft 115 is provided with a lantern-pinion 115a, Fig. 9, meshing with the driving gear 107 for actu tion directly therefrom, the gear ratio tween the two being such that the cam will be rotated 180 in each operation of the transmitter mechanism initiated by turning in an alarm. The completion of such operation leaves the cam about in the position shown in Fig. 3, with contacts 16a, 17a open. When however, the winding lever 108 is depressed to fully rewind the spring the cam is rotated 180 counterclockwise and thus closes the contacts. Shaft 115 also has a gear 116 (Fig. 6) meshing with and driving a lantern pinion 117 loose on shaft 118 (which drives the cam 42a, Fig. 3) but having a one-tooth ratchet 119 cooperating with a spring-actuated pawl 120 carried by gear 121 fixed on said shaft 118. It will therefore be seen that the spring in barrel 106 may be wound without reverse rotation of gear 121 and cam 42a but that when barrel 106 and driving gear 107 are driven by the spring, in the direction of the arrow, the gear 121 and shaft 118 will be rotated counterclockwise as seen in Figs. 3 and 6.

Gear 121, Fig. 6, meshes with a lantern inion 122 fixed on shaft 123 on which is xed a gear 124 which in turn meshes with a lantern pinion 125 on shaft 126 carrying a gear 127 meshing with a lantern pinion 128 on shaft 129. The latter has a fan governor 130,

Fig. 4, which is rotated at a high rate of speed by the gear train described. The fan blades are mounted on a rod 131, Fig. 5, extending through the hub 132. By loosening the setscrew 133, which holds the rod in adjusted position, the inclination of the fan blades or vanes can be varied to regulate the govern ing effect.

Reverting to Fig. 6, when the mechanism is actuated by the driving spring the gear 127 is rotated counterclockwise, but rotation of the gear, and consequently rotation of the contact-actuating cams (shown at 41a and 42a in Fig. 3) are prevented under normal conditions by the locking dog 134 in the path of a detent 135 on the said gear 127. This dog 134 is mounted on a pivot or shaft 136 journaled in the side plates 100, 101, and is held in locking position by the armature 137 of the. transmitter magnets 104. When these v 127 and permitting the mechanism to operate 7.

rocked clockwise to release the mechanism,- it will be evident that merely closing themagnet circuit will not of itself result in restoring the dog, and accordingly I have provided mechanical means for effecting the restoration,- such means being preferably actuated by or dependent upon the winding 0 the spring which drives the mechanism. also prefer to have the restoration effected at the completion of the winding operation.

I If, then, the spring winding is not completed,

that is, if the spring is'not fully wound up, the locking will not be effected, and contacts 16a, 17a (Fig. 3) will not be closed by cam 41a since, as explained above, actuation of gr. the winding lever 108 far enough to fully rewind the spring, is necessary to restore cam 41a to its normal position. It'is possible to wind 'the spring partially and restore the locking dog 134 to locking position by hand,

in which case the mechanism would be locked; but contacts 16a, 17a would remain open and the trouble bell would therefore continue to ring until the rewinding is fully performed. The mechanical means referred to just above, for restoring the locking dog'to locking or normal position, are shown in Figs.

6, 6a, 7 and 8. As shown, the pivot 136 carries, alongside of the .dog 134, an arm 140 having a finger 141 extending forwardly to cooperate with the vertical arm 142 of a bell-crank lever fulcrummed in the side plates at 143 and having a forwardly extending arm 144. The latter carries a pivoted finger 145 held by a spring 146 against a stop 147.

5 The forward end of the finger is in position to be engaged and depressed, as in Fig. 8, -by a cooperating finger 148 adjustably fixed on shaft 115, which, it will be remembered,

is rotated counterclockwise 180 by the com- 30 plete depression of the winding lever 108. The finger 148 is so positioned on the shaft that the engagement of finger 145 and the consequent depression thereof occurs just before, or just as, or just after, the winding lever reaches the position inwhich the spring is fully wound up. The finger 148 is then about in the position shown in Fig. 6. It

is also of advantage to have this finger 148 adjustable on the shaft, so that it may be made to engage the finger 145 and release the lever 142, in the manner described below,

at any predetermined time during the opera- "tion of the winding lever; the circumstances of the use of the transmitter may well warrant earlier operation of this finger, and in the preferredarrangement, indicated here it may be desirable to make the resetting of dog 134 more positive and certain by having the engagement of finger 148 with finger 145 occur slightly before the windin lever reaches the fully wound position. W en the mechanism is actuated b the driving s ring the shaft 115 is rotate clockwise an the spring 146 permitsthe fin er 148 to pass the other without the possibihty of their becoming locked together. At its upper end the lever 142 is provided with a laterally extending cam-stud 149, and the arm 140, actuated by the armature 137, is provided, alongside of the finger 141, with an upwardly arched f cam-finger 150, overlying the stud 149. Now I when the lever arm is swung clockwise b the depression of finger 145 as described a ove, the stud 149 will engage the finger 150 and cam the same upwardly, thereby restoring the'dog 134 to locking position and restoring the armature 137 to the normal position, close enough to the poles of the relay magnets to be held by the relatively weak magnetic field. This operation is illustrated in Fig. 8. The upper end of lever arm 142 is also provided with a recess 151 so located that whenthe dog 134 is in looking or normal position the finger is above the recess, as in Figs. 6 and 6a. When, however, the magnets 104 let go of the armature and permit the spring 138 to rock the dog downwardly out of locking position the end of the finger is carried below the shoulder, forming the upper edge of the recess, whereupon the spring 152 swings the lever 142 counterclockwise and thereby brings the shoulder over the finger, thus holding the entire armature assembly down, with the dog out of locking position. This makes it impossible to depress the armature manually far enough to restore the dog to locking position without first shifting the locking control lever 142 out of engagement with finger 141, and since it scarcely is possible for these. operations to occur as a' result of mere carelessness on the part of the attendant it will be seen that in the absence of actual intent to mishandle the apparatus the attendant cannot restore the system to normal condition after an alarm has been turned in without complete rewinding of the driving spring. Thus complete reliance need not be placed on the trouble bell, ringing as long as contacts 16a, 17 a remain open, as a sole indication whether the apparatus is fully rewound andlocked.

To arrest the mechanism after the cam 42a has made a predetermined number of revolutions the cam shaft 118, Figs. 3,6 and 9, is

provided with a rotatably adjustable detent 155 and on the spring drum 106 is a circumferentially adjustable stop 158, fastened to the drum by screws 156 passing through slots, not shown. Since the stop and detent can rotate only in the same direction, by reason of the gearing between the drum 106 and the shaft 118, it will'be seen that when the stop and detent meet as in Fi 9, with the detent urged in the direction 0 the arrow (clockwise) by the driving s ring, and the drum also urged clockwise, t e drum is arrested. If the gear ratio between the drum and the shaft is sufliciently high the detent can make several revolutions before the stop, movin from themormal position (Fig. 6) occupie when the drivingspring is fully wound, can come into the path of the detent for engagement thereby as in Fig. 9. Assuming a given gear ratio, the number of revolutions of the cam shaft 118 will depend upon the timing of the stop and detent, as will also the exact point (1n the final revolution) at which the code cam will come to rest. In the mechanism shown the construction and adjustment are such that between release of'the mechanism .by the dog 134 and engagement of the stop and detent the cam will make somewhat less than four complete revolutions, leaving the lug 135 about 180 beyond the locking position shown in Fig. 6. Then when the driving spring is rewound, release of the winding lever permits the spring to carry the lug on around to locking position, thusgiving exactly four complete revolutions between release and relocking of the'lug. To permit a greater number of complete revolutions it may be necessary to shorten or rearrange the stop 110, Figs. 4 and 9, to permit suflicient movement of the spring drum in the driving direction.

Upon reference to Fig. 9, and remembering that when driven by the driving spring the driving gear 107 and stop 158, and gear 121 v and detent 155, all revolve in the clockwise direction, it will be seen that forcible rotation of the driving gear in the same direction after the stop and detent have engagedwould result either in breaking some part or disturbing the adjustment of the stop or detent or .both. If the winding lever 108 were fixed on the drum shaft the result referred to might be occasioned, for example, by improper actuation of the lever in attempting to rewind the spring, but with the lever loose on the shaft, as previously described, lifting the lever from the position of Fig. 6 or Fig. 9

can do no more than bring the lever up against the spacing bar 157 extending between the twoside plates at. the top. Also, in the con- 6, 7 and 8,1 the loc as in' Fig. 10) the spring 163. Hence, with a s ring s ciently strong for the purose an yet not so stron as to prevent unocking by the magnets w en fully energized there is no necessit for mechanically restorposition (for engagement with the 162. 7

ing the do to 100 'ng position. But to in-' 162 the control lever 164 swings leftwardly and brings the shoulder under the finger, as in Figs. 10a and 11, thereby positively holding the dog out of locking position until, by complete rewinding of the driving spring,'the arm 167 engages the fin er 168 and swings the control lever rightwar 1y. Whereupon the spring 163 (magnets 160 being deenergized) draws the dog 161 down into locking position. Reference to Fig. 1, the circuit in which this form of the apparatus is used as noted below shows the further necessity of holding the dog 161 out of locking position, in that as soon as the mechanism is set in o eration contacts 16, 17 open, thuso ening t e series circuit through magnet 18 {hr Fig. 10, magnets 160), deenergizing the same so that the dog 161 would move immediately into looking position by reason of the spring 163, if it were not otherwise held by shoulder 165 engaging finger 166. Otherwise than as noted in this paragraph the apparatus shown in Figs.'10, 10a and 11 is the same in construction and operation as that shown in Figs. 3 to 9 inclusive.

ets rock the dog 161 counterclockwise to disengage the latter from the lug In some cases it ma be necessary or desirable to have the 100 'ng dog 161, Fig. 10, restored to locking position by positively acting means instead of or in addition to the spring 163. If so, the desired result may be obtained by the means shown in Figs. 10b, in which a downwardly arched finger 166a is provided in rigid connection with finger 166. Lever 164a is provided with a lateral stud 164b.' Itwill therefore be seen that when lever 164a is rocked clockwise in the opera- Y Hence for this system, in which: the code transmitter magnet is normally deenergized, or too weakly energized to actuate its arma-- ture, the transmitter of Figs. 10,1011 and 11 3 is especially adapted. Upon reference to the system illustrated in Fig. 2 it will be seen the etent b is released (to permit rotation in the direction of the arrow) by downward movement of the armature 300 under the influence of the spring when the normally energized magnet 18a is deenergized. Hence in this system I use the apparatus shownin Figs. 3 to 9 inclusive.

It is to be understood that the invention is u not limited to the specific constructions herein illustrated and described but can be embodied in other forms without departure from the spirit of the invention as defined by the appended claims. so I claim- '1. In a transmitter mechanism, in combination, a set of circuit-controlling contacts, mechanism associated with said contacts to operate the same and having a driving #5 spring, means for putting the sprin under driving tension, a detent normally docking the contact-o erating mechanism and shiftable automatically to release the same, electromagnetic means for holdin the detent in locking position, a lever assoclated with the detent to revent movement thereof into locking position before the sprin has been fully tensioned, means actuated by the spring-tensioning means for rocking said lever to permit movement of the detent into locking position; and means operating when the spring tensioning means 1s actuated, to shift the detent into lockin position.

2. In a transmitter mec anism, in combination,'a set of circuit-controlling contacts, mechanism associated with said contacts to operate the same and having a driving spring, means for putting the sprin under driving tension, electromagnetical y controlled means for locking and unlocking the contact-operating mechanism, separate automatic means for arresting the mechanism after a cycle of operation, means associated with the said electromagnetically controlled means and engageable therewith to prevent locking operation thereof, and means actuated automatically at any stage of the spring-tensioning operation for disengaging said associated means and shifting the electromagnetically controlled means into locking position.

3. In a transmitter mechanism, in combination, a set of circuit-controlling contacts, actuating means for the contacts having a driving spring, automatic means for arresting the said actuating means after a complete cycle of operation, an electroma etically controlled member for locking sa1d actuating means and movable into and out of predetermined locking position, a lever for moving said member, a second member actuated by the driving-springand movable into cooperation with said lever only when the drivin spring is under predetermined tension, an meansfor tensioning the driving spring comprising a stud associated with the driv-. ing spring and movable to a ply tension to the latter, a tensioning mem er engageable with said stud to actuate the same in the tensio'ning direction only, a second stud asso'-- ciated with the drivin sprin a detent engageable with the sai 'secon stud preventing accidental eircessive' unwinding of the s ring, and means preventing engagement oi t e tensioning member with the second stud and consequent accidental forward motion of the contact-actuating means during the sprin -tensioning operation.

4. a transmitter mechanism, in combination, a set of circuit-controlling contacts, driving], meansfor actuatin the contacts throug a predetermined cyc e of operation, means for arresting the said contact-actuating means,. and electromagnetically-controlled releasable means for locking the contact-actuating means, comprising an electromagnet, an armature cooperating therewith, a rotating member associated with the contact-actuating means, a locking detent associated with the said armature and movable into and out of cooperation with the said rotating member, an auxiliary spring tending to hold the said detent out of cooperation with the rotating member a second rotating member associated with the contact-actuating means, a lever movable into and out of cooperation with the said second rotating member and engageable with the said detent for moving same into lockinlg position, and further means associated wit the said lever for positively holding the de-. tent out of locking position while the contact-actuating means is traversing its cycle of operation.

5. In a transmitter mechanism, in combination, a set of circuit-controllin contacts a rotating member associated wit the said contacts to operate the latter, a movable ratchet engaging the rotating member to operate the same only when moved in a forward direction, reversible driving means to operate the said ratchet, a second set of circu'it-controlling' contacts, a cam operating the said second set of contacts and actuated by the said reversible driving means means for arresting the driving means after the said rotating member has traversed a predetermined cycle of operation, means'for reversing the driving means to operate the said cam through a second predetermined cycleof operation, and electroma etically controlled means for locking an unlocklng'the driving means. 6. In a' transmitter mechanism, in combination, a set of circuit-controlling contacts,

mechanism associated with said contacts to operate the same and having a driving spring, means for putting the spring under predetermined tension and releasa 1e means 5 to permit locking of said contact-operating mechanism only when the driving spring is under predetermined tension, comprising a rotating element actuated by the spring, a locking detent movable into and out of cooperation with said rotating element, a second rotating element likewise actuated by the spring, a lever movable into and out of cooperation with both the second rotating element and the said locking detent, a finger projecting from the detent and a shoulder on the said lever engaging the said finger to hold the detent out of locking position when the driving spring lacks full tension.

In testimony whereof I hereto afiix my signature.

GEORGE F. HARTER. 

